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What is Boron carbide

Boron carbide (chemical formula approximately B4C) is an extremely hard boron–carbon ceramic, a covalent material used in tank armor, bulletproof vests, engine sabotage powders, and numerous industrial applications.  It was discovered in 19th century as the by-product of metal boride reactions.  Controversy remained as to whether or not the material had this exact 4:1 stoichiometry, in practice, the material is always slightly carbon-deficient concerning this formula, and X-ray crystallography respent that its structure is highly complex, and a mixture of C-B-C chains and B12 icosahedra. These features argued against a very simple exact B4C empirical formula. Because of the B12 structural unit, the chemical formula of "ideal" boron carbide is often written not as B4C but as B12C3. Boron carbide has a complex crystal structure typical of icosahedron based borides. There, B12 icosahedra form a rhombohedral lattice unit surrounding a C-B-C chain that resides at the center of the unit cell, so both carbon atoms bridge the neighboring three icosahedra. The B12 icosahedra and bridging carbons form a network plane that spreads parallel to the c-plane and stacks along the c-axis. The lattice has two basic structure units – the B12 icosahedron and the B6 octahedron. Because of the little size of the B6 octahedra, they cannot interconnect. Due to the B12 structural unit, the chemical formula of "ideal" boron carbide is often written not as B4C but as B12C3. Boron carbide is famous for a robust material having extremely high hardness, a high cross-section for absorption of neutrons (i.e., good shielding properties against neutrons), stability to ionizing radiation, and most chemicals. Its Vickers hardness (38 GPa), Elastic Modulus (460 GPa), and fracture toughness (3.5 MPa·m1/2) approach the corresponding values for diamond (1150 GPa and 5.3 MPa·m1/2). Boron carbide is a semiconductor with electronic properties dominated by hopping-type transport. The energy band gap depends on composition and the degree of order. The band gap, with multiple mid-bandgap states, is estimated at 2.09 eV, complicating the photoluminescence spectrum. The material is typically p-type. If you are looking for high quality, high purity and cost-effective Boron carbide, or if you require the latest price of Boron carbide, please feel free to email contact mis-asia.

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